Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. 09/464,427, entitled: REGISTRATION MECHANISM AND METHOD, filed in the names of Michael L. DeCecca, Joseph A. Watkins, and Duane B. Kirk each of which is assigned to the assignee of this application.
The invention relates to camera manufacturing equipment and systems and more particularly relates to a dark-box transfer apparatus and manufacturing system.
A variety of procedures are known in which one-time use cameras are loaded with film, and the film is prewound in the dark. An example of this kind of procedure is disclosed in U.S. Pat. No. 5,689,876. During film loading, a onetime use camera frame assembly, that is, a camera or incomplete camera subunit, is moved through a series of workstations by a rotary turntable or a conveyor. A dark box encloses the film loading workstations. Camera frame assemblies enter and leave the dark box through light-lock doors. Dark conditions are maintained during film loading steps until the camera frame assemblies are light-tightly closed by installation of camera backs.
For film loading, accurate positioning of the camera frame assemblies in the workstations is critical. Rapid movement from station to station is highly desirable. Accurate positioning of the camera frame assemblies during transit between workstations is not important. U.S. Pat. No. 4,331,229 discloses a manufacturing machine in which pallets are moved from the station to station on a conveyor belt. At each station, the pallet is lifted from the belt and accurately positioned for access by the tooling of that workstation. The manufacturing machine of this patent provides accurate positioning at the workstations and can provide rapid movement from station the station. The manufacturing machine has the shortcoming; however, that exacting measures must be taken independently, at each station, to insurer accurate positioning. This may also be a strength, in general use under lighted conditions, since it would appear that a workstation could be serviced without necessarily disaccommodating the remainder of the manufacturing machine. Dark conditions would make this impractical, since use of light during servicing would avert usage of all the workstations.
A variety of different apparatus and methods are known for transporting and registering pallets and workpieces, such as U.S. Pat. Nos. 3,888,341; 4,148,400; 4,201,284; 4,394,897; 4,850,102; 4,854,532; 5,058,251; 5,062,188; 5,167,589; 5,197,172; 5,226,211; and 5,242,043. Features disclosed in one or more of these patents include use of a transfer bar, pallet clamping, and pallet locating using multiple, orthogonally arranged support points. Various of the disclosed devices have a number of shortcomings, such as: complexity; excess moving mass that is necessary for a high weight carrying capacity, but is excessive for light, rapid manufacturing; overconstrained registration mechanisms requiring more than a minimum of precision parts, and pallet movement systems that require precision parts that are subject to high rates of wear during use.
It would thus be desirable to provide an improved dark box-transfer apparatus which is relatively simple; suitable for light, rapid manufacturing; and is subject to a relatively low rate of wear on precision parts.
The invention is defined by the claims. The invention, in its broader aspects, provides a transfer apparatus that has a table having a sequence of datum units. A transporter is aligned with the table. The transporter is incrementally advanceable past each datum unit. The transporter can carry pallets. A rigid bolster, that moves separately from the transporter, is aligned with the transporter and table. The bolster is movable relative to the table between a lowered position and a raised position to the lift and lower the pallets. The bolster is synchronized with the transporter so that the pallets can be lifted and lowered in each of a sequence of stations. A plurality of locating units are joined to the bolster. Each locating unit is aligned with a respective datum unit. The bolster lifts the pallets on the locating units and clamps the pallets against the respective datum units. A manufacturing system includes the transfer apparatus, pallets, a series of manufacturing stations, and a conveying system for moving the pallets through the manufacturing stations and transfer apparatus.
It is an advantageous effect of at least some of the embodiments of the invention that an improved dark box-transfer apparatus is provided which is relatively simple; is suitable for light, rapid manufacturing; and is subject to a relatively low rate of wear on precision parts.